Ultrasonically Assisted Hammer-Action Penetrators in Planetary Regolith

This paper describes the effects of combining ultrasonic vibration with hammer-action style penetrators, such as the HP3 probe on the InSight mission. By synchronizing short pulses of vibration with the impact of the hammer, the number of hammer strikes required to reach a specified depth was reduced by over a third in some cases, depending on the sand and amplitude of vibration used. Additional investigations looked at comparing the performance of pure hammering with pure pulsing, allowing recommendations for operational procedures if this technology were to be taken forward in the future

Preparations for Variable-Gravity Regolith Penetration with an Ultrasonically-Active Probe

The set of experiments proposed in this paper intend to investigate the properties of ultrasonic penetration through granular materials in hypergravity. As part of ESA's 6 th 'Spin Your Thesis' campaign, the University of Glasgow will be allowed to use the Large Diameter Centrifuge at the ESTEC facilities in Noordwijk, Netherlands, to achieve these hypergravity conditions. This paper describes the progress of the design and manufacture of the experimental apparatus, analysis of structural integrity to insure the rig can be subjected to the rigors of hypergravity, and discussion of the anticipated results and implications

Push-and-Twist Drillstring Assemblies

Deep drilling using a rigid drillstring requires the assembly and disassembly of multiple drill pipes. The interfaces between these pipes provide a challenge for automation because they must transmit large drilling forces and movements while, at the same time, minimise the actions and forces that are needed to make or break the interface. A geometry which can address these requirements has been suggested by the authors. This approach would use a push-and-twist bayonet system to engage drill pipes, with torque transmission through the bayonet studs. A variety of L-shaped and T-shaped bayonet paths have been proposed to ensure that separation of specific drill pipes can be achieved through a combination of clockwise and counter-clockwise rotation and single-point clamping. Sustained drills into a variety of media are used to show that percussive impulses are transmitted across the interface, whilst ensuring that the drill interface is able to withstand the shock loading associated with hammer-drilling. These tests are repeated and contrasted to control experiments using a single-piece control drillstring, which allows the performance of the interface and any degradation over time to be quantified. Results suggest that the bayonet-style connection performs well with no significant performances losses encountered or structural degradation noted

An experimental study of ultrasonic vibration and the penetration of granular material

This work investigates the potential use of direct ultrasonic vibration as an aid to penetration of granular material. Compared with non-ultrasonic penetration, required forces have been observed to reduce by an order of magnitude. Similarly, total consumed power can be reduced by up to 27%, depending on the substrate and ultrasonic amplitude used. Tests were also carried out in high-gravity conditions, displaying a trend that suggests these benefits could be leveraged in lower gravity regimes.Peer ReviewedPostprint (published version

Determinants of Reverse Marketing Knowledge Transfer Potential from Emerging Market Subsidiaries to Multinational Enterprises’ Headquarters

Emerging markets are becoming increasingly important for multinational enterprises because of their high growth potential and future prospects. The unique circumstances in emerging markets lead to increased pressure to offer creative marketing solutions that can be leveraged across the multinational network. Setting up subsidiaries to tap into these markets offers companies the opportunity to integrate in the local community and access its knowledge-base for local and global innovations. Literature, however, reveals that emerging market subsidiaries have been largely ignored concerning their potential for reverse knowledge transfer, and marketing initiatives are expected to be developed in mature, developed markets. Our paper fills this gap in research and contributes to extant literature by identifying factors at unit, relationship, and knowledge levels influencing reverse knowledge transfer potential specific to marketing knowledge from emerging market subsidiaries. The conceptual discussion leads to study propositions and conceptual framework

Ultrasonically assisted penetration through granular materials for planetary exploration

Space exploration missions often use drills or penetrators to access the subsurface of planetary bodies. Protected by the conditions experienced at the surface, these regions have potentially been untouched for millennia. As such, the subsurface is a very attractive option for scientific goals, be it the search for extra-terrestrial life, to examine the history of the planet, or to utilise underground resources. However, many issues arise in such a task. Every other rocky body in our solar system possesses a surface gravity lower than our own, resulting in a lower available weight for a spacecraft to ‘push’ on a penetrating device. Add to this the low power availability and complications regarding remote operation, and this becomes a very difficult process to achieve. Mole devices which burrow through the ground whilst tethered to a surface-station to provide power and data have shown great promise in this regard. Using an internal mass to ‘hammer’ themselves into the ground, special care is required to ensure internal components are not damaged, and that they can arrive at their target depth in a reasonable period of time. There is continuous development in these types of drilling and penetrating technologies and anything that can penetrate with a lower weight-on-bit (WOB), and consume less power, could potentially be extremely useful for these situations. High powered ultrasonic vibrations have been shown to reduce operational space and forces required in cutting bones for surgery. Additionally, they have been successful in reducing WOB requirements for drilling devices through rocky substrates. To maximise penetration depth, it is often favourable to progress though granular material rather than solid rock, however this also provides its own set of problems. This work looks at applying ultrasonic vibration to penetrating probes for use in granular material, with the aim of utilising it in low gravity or low mass scenarios. Before this can be done however, the regolith used for testing must be fully characterised and consistent preparation methods established, ensuring that all other effects are accounted for. An ultrasonically tuned penetrator was designed and manufactured, and the effects it had on the surface of sand were investigated using a high-speed camera and optical microscope. It was found that regions of sand immediately surrounding the penetrator were highly fluidised, localising any deformations to a small radial distance. Penetration tests were then conducted that showed ultrasonic vibration significantly reduces the penetration forces and therefore the overhead weight required, in some cases by over an order of magnitude. A similar effect was seen in power consumption, with some instances displaying a lowered total power draw of the whole system. Experiments were then conducted in a large centrifuge to examine the trends with respect to gravity. Gravitational levels up to 10 g were tested, and the general trend showed that ultrasonic penetration efficiency indeed increased at lower gravities, suggesting that the force reduction properties would be enhanced at lower levels of g. Finally, the first steps to applying this technique as a fully-fledged penetration device were conducted. These tests oversaw combining ultrasonic vibration with the established hammering mechanism used by mole devices. Comparing this against a purely hammering penetration, it was found that the addition of ultrasonic improved performance significantly, greatly reducing the number of strikes required to reach the same penetration depth. To conclude, the work presented in this thesis shows the potential that ultrasonic vibration can have with advancing low gravity/low mass penetrating devices. Reducing both the weight and power requirements can be a huge boon to small spacecraft, and the potential use as subsurface access or anchoring devices makes it an attractive avenue for future research and development

Ultrasonic Auger for Narrow-Gauge Borehole Drilling

An ultrasonic auger was designed, manufactured, and tested in glass microspheres to investigate force and torque reducing effects upon application of high-powered ultrasonic vibration. It was found that whilst vibration had no effect on overhead force during rotary augering, the torque was reduced by up to 30%, depending on amplitude of vibration

Development of a robust mating system for use in the autonomous assembly of planetary drill strings

Volume-constrained robotic missions seeking to obtain samples from beneath a planetary subsurface may wish to use a rigid drill string consisting of multiple, individual drill bit sections connected together, as opposed to a single, lengthy drill bit. To ensure that drill strings can be assembled and disassembled reliably, it is essential that a robust connection system be used. The authors propose a geometry that seeks to address the requirements of such a mating interface. The proposed solution is based on the bayonet interface, using L- and T-shaped so-called female grooves and male studs connected and disconnected together through a series of clockwise and counterclockwise rotations and single-point clamping events. This routine allows the transfer of both percussion through the drill string and torque in both directions of rotation, while permitting the accurate disconnection of individual drills bits at the required location. Sustained laboratory and field drilling operations suggest that bayonet-style connections offer a reliable solution to the problem of autonomous assembly and disassembly of drill strings in a planetary exploration setting. This paper discusses the development of such a connection system, based on the bayonet connection, which has been implemented in the overall architecture of the Ultrasonic Planetary Core Drill (UPCD). The design trade-off study, which sought to evaluate the use of the bayonet system in comparison with the more conventional screw thread interface, will be discussed, alongside experimental results from percussion transmission testing and drill string assembly testing

Ultrasonically Assisted Penetration Through Granular Materials

Gaining access to the subsurface of planetary bodies is troublesome for a number of reasons, but particularly due to the low gravity encountered resulting in a lower available weight of spacecraft. A lower weight-on-bit (WOB) often results in sub-optimal drilling, and without complex anchoring or thrusting systems a planetary lander can only impart as much force as it weighs. This work investigates the use of ultrasonic vibration in assisting penetration through granular material. Compared to non-ultrasonic penetration, required forces have been observed to reduce by over a factor of 12. Similarly, total consumed power can be reduced by 28%, depending on the substrate and ultrasonic amplitude used. Tests were also carried out in high-gravity situations, displaying a trend that suggests these benefits would strengthen in lower gravity regimes

FDIR for a Biologically Inspired Trenchless Drilling Device

Failure Detection, Isolation and Recovery (FDIR) of autonomous systems working in hazardous conditions is essential. Methods of detection and recovery without intervention are required. This work describes the failure modes currently identified with an autonomous biologically inspired trenchless drilling robotic system. Inverse Simulation is used for detecting failures and is demonstrated on a simulation model of the robotic system. Results from the experiments, show that Inverse Simulation can be used to detect and identify system failures